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ananyo writes "Organisms, including humans, are often assumed to be hard-wired by evolution to try to make optimal decisions, to the best of their knowledge. Ranking choices consistently — for example, in selecting food sources — would seem to be one aspect of such rationality. If A is preferred over B, and B over C, then surely A should be selected when the options are just A and C? This seemingly logical ordering of preferences is called transitivity. Furthermore, if A is preferred when both B and C are available, then A should 'rationally' remain the first choice when only A and B are at hand ... But sometimes animals do not display such logic. For example, honeybees and gray jays have been seen to violate the Independence of Irrational Alternatives, and so have hummingbirds ... Researchers have now used a theoretical model to show that, in fact, violations of transitivity can sometimes be the best choice (original paper) for the given situation, and therefore rational. The key is that the various choices might appear or disappear in the future. Then the decision becomes more complicated than a simple, fixed ranking of preferences. So while these choices look irrational, they aren't necessarily."

That, and/or they discovered that humans aren't the only ones who make decisions that seem unreasonable and arbitrary to a third party observer.

Such as drinking crap like Tab or Mountain Dew. It may give you kidney stones, do a poor job of hydrating, lack vital nutrients, and only contain monomers which provide nothing more than short term energy, but it tastes sooo good.

I don't think "enjoying" is something they can easily determined in honeybees or birds. They basically hypothesized that choices can be made based on future availability rather than just current state (i.e. "wow, animals can think!").

Or to put it in your terms: even if you didn't particularly like Twinkies, you may have hoarded them right before Hostess went bankrupt since you didn't know if you'd ever get another chance.

This will be the perfect excuse for every situation the human being can't explain his moral decisions, like why do we act stupid when in love, why do some people chose to go to war and why did they sack Conan from the Tonight Show.

Maybe, although you're consciously unaware of it, your body craves the carbohydrates, proteins, and lipids that cheap pizza provides. And then other times, despite the fact that it's dinner time, you had a late lunch and you don't currently need any energy input, especially considering that you haven't used much energy sitting around browsing Slashdot.

There may be randomness in decision making sometimes, but basing a decision off of 'this is what I feel like' isn't random, you're just not making a conscious

Organisms, including humans, are often assumed to be hard-wired by evolution to try to make optimal decisions, to the best of their knowledge.

What about humans have we seen to suggest humans are rational or are hard-wired make 'optimal' choices?

For biologists (or economists) to make this assumption has always struck me as terribly flawed, because in the real world, we see quite the opposite.

In the case of humans, cultural biases and any number of things skew our decision making to be less than perfect. And any theoretical model which assumes otherwise is pretty much the equivalent of assuming a perfectly spherical cow.

TFA is badly written in this sense that so called irational is in fact not the way choices are made but our thinking about the choices themselves as it is apparently detached from the past and future. As in example they gave: if you usually have preference a b,c etc then in situation when different combinations are presented choices are still to be made consistently but apparent choices are not and the reason is not that the animal is less consistent but that the preference is not absolute but depends on th

In the case of humans, cultural biases and any number of things skew our decision making to be less than perfect. And any theoretical model which assumes otherwise is pretty much the equivalent of assuming a perfectly spherical cow.

Hell, if you have two models of product, say, A and C, where A is better and more expensive than C, introducing a mid-range product B can skew sales towards A. I.e., if you have A and C, C sells more (generally because it's cheaper), but by having B, you can drive sales towards A

All I learned was that a model needed more parameters, which in the pure sciences is the obvious conclusion. Yet here it seems to be a revelation, following years of people discarding animals as just being incompetent problem solvers.Ascribing enough intelligence to consider such a problem, while stating that it is a basic survival need to solve the problem, seems like a seriously conflicted theory. Failure to solve the problem seems, in other words, to require more cognition than a simple instinctive decis

Its important to reinforce the fact that violations in transivity, while rational, may never be appropriate under some circumstances.

in a TSA checkpoint. is your transivity under 3 ounces? did you remove your A and B before walking through C?
if transivity is for loading and unloading only. dont just put your blinkers on either or C will tow your A to B.
if you clicked through the EULA for windows 8 without reading, boy will you ever be sorry. You cant violate transivity or Internet explorer will res

If you're trying to find a balanced diet using many ingredients and take one of those away, the rest of the diet might change totally. For example, let's assume the removed ingredient was a very good source of protein. Now you're scrambling to replace it with other protein sources, introducing foods you didn't need before. And now you're high on carbs, so your high-carb food goes out and is replaced by something else, so now you lack vitamin D so we add another new food and so on. It's a set ordering not a factor ordering because if you've eaten beef all week you'd rather eat pork, even if you prefer beef.

They don't claim to have a realistic model of the situation: They showed a very simple model in which the rational behavior contains an apparent violation of transitivity. And they didn't need to introduce a variety of nutrients to obtain it. This makes their model better, in the sense that it is simpler.

Unpredictability is a necessary trait when evading predators, so an organism that always chose C when C > B and B > A would be more predictable and easier for an intelligent predator to catch. This tendency not to would need to be deeply hardwired into the nature of the organism, since otherwise it would rarely kick in and, again, the organism would be easy prey. Optimising a small subset of a problem (and the whole problem is survival and procreation) often leads to locally optimal yet seriously globally subobtimal solutions. The greedy algorithm works on only a few cases (sometimes called monoids if I remember my combinatorial optimisation text, though that was over a decade ago); and with only slightly more complex problems it is often easy to construct pathological cases where the greedy algorithm gets it wrong. I see this result about organisms as another example of the principle that straightforward rational solutions are only the best when the problem is straightforward and simple.

Evolution happens without any intentional action by the participants. The proto-eagle did not decide, "it is getting too crowded in this niche, let me fly higher, evolve keener eye-sight, may be a second foeva, the current one is not good for distance over 1 mile, and become an eagle". Many million proto-eagles made many ad-hoc decisions, and the ones that happened to hit on the right strategy, over many thousand generations became eagle. What you learn from evolution is statistical result of millions of e

Scientist always thought that choices made by animals could be modeled using simple algorithms such as if A is preferred over B and B is preferred over C, then if A and C is offered the animal would choose A. When the animal being observed didn't choose A they declared a transitivity violation. What they have discovered is that there model was flawed and what goes into making one choice better than another is more involved than first thought. As such, there is not transitivity violation and the animals st

And it's a bit like when you are eating - if you love roast beef with mashed potatoes and have had that every day for a month, then you would pick something else just to get a change as long as you know it's edible, you may even be willing to pick food that you usually avoid.

The point is that nature has provided some species the ability to get bored with a certain food to ensure that there is a variation in the intake of nourishment and avoid deficiencies and dependability on a certain source.

I had a prof who would take a vote on which day we would have our test. Once he gave us the choice of next week monday or friday. The vote was overwhelmingly monday (I can't remember but something like 2/3). Immediately after he realized that wednesday was also an option, so we had a re-vote. Friday won out with a majority (not plurality) vote.
So, no, I don't think that guans are wired for logical decision making. Animals, I still hold out hope for.

It might also have to do with competition. If there's little competition for my preferred food source, I will eat it last, knowing it will last longer. My wife hates dark chocolate, but I prefer it, so if there's a bag of chocolate bars and dark chocolate, I'll dig into the milk chocolate first, knowing that my wife will actively consume those as well, then when they're gone, I still have the dark chocolate to enjoy afterwards, while she's without.

Yes, this is the point of the article. Your ability to look into the future may make you change your current preferences. You know the dark chocolate won't run out, so to maximize your chocolate intake, you eat the milk chocolate first. If your wife were visiting her sister for an extended period of time, you'd probably eat the dark chocolate first, because you like it better.

This is, of course, not nice (wife "I bought the dark for you and the milk for me"), but is probably rational.

I would argue that the problem isn't with transitivity, but with assuming that value is fixed around objects. In reality, value fluctuates according to circumstances.

I might give you $100 for your bar of dark chocolate because I love it that much and I don't have any. But if I have 5 tons of delicious dark chocolate in my basement, I'm not going to give you even $1 for your bar.

My wife hates dark chocolate, but I prefer it, so if there's a bag of chocolate bars and dark chocolate, I'll dig into the milk chocolate first, knowing that my wife will actively consume those as well, then when they're gone, I still have the dark chocolate to enjoy afterwards, while she's without.

So, you purposefully over indulge, pigging out on the thing your wife likes to intentionally deprive here, meanwhile stashing back stuff you know she won't eat?

My wife loves chocolate as well, but hates to eat it because she likes being skinny more than she likes eating chocolate (and if you ask any woman, the two are mutually exclusive). So, if I have chocolate in the house, I must compete with her and ensure that I eat most of it, otherwise she gets upset.

You know, I never liked the fried chicken or watermelon stereotypes. Who the hell doesn't like fried chicken or watermelon?

I'm with you on the fried chicken part, but personally I've never been a big fan of watermelon.

FTR, the black people/watermelon stereotype is less about liking the fruit, and more about stealing them. Not sure where it originated, but I have seen a gum adverts from the early 20th century that depicts a black-faced child sneaking under a fence to snatch a melon or two. Can't seem to find it on Google, though...

Anyway, stereotypes exist because someone observed that, on average, foo is true of a significant portion of demographic bar. They simplify decision making at the expense of some accuracy.

Some stereotypes exist because of observed behavior. Some exist because of preconceived notions ba

My wife loves chocolate as well, but hates to eat it because she likes being skinny more than she likes eating chocolate (and if you ask any woman, the two are mutually exclusive).

Right: You're the one perpetuating misogynistic stereotypes, but I'm the guy who knows nothing about women...

...and you are the one who missed that the GP was making a statement of fact about one particular woman who they know well, not making a stereotypical generalisation. But since you bring it up, my wife has also said this to me pretty much verbatim...

So, the phrase, "and if you ask any woman..." doesn't imply generalization? Sure sounds that way to me.

The two things that he was referring to were "eating chocolate" and "being skinny". Which, pretty much are mutually exclusive to men and women alike....

You're cherry picking. Fact is, OP made a broad generalization about women, and I called them on it. If you're getting anything else out of my comment then it's something you've come up with on your own.

One of my pet peeves with discussions on evolution is the assumption, in general, that any given trait or behavior evolved for a particular reason, or that any one concept such as "logical rationality" can explain the whole evolution of a single such trait. In fact this sounds more like intelligent design than evolution. It's an interesting exercise to track a trait through evolution, but there's a fine line between that and presupposing that every behavior must occur due to some underlying logic.

We're talking about behavior that evolved due to an absurd amount of chaos; how was it not obvious that a "decision becomes more complicated than a simple, fixed ranking of preferences"? And who gets to decide what's "rational"... from a basic evolutionary perspective, anything that has evolved to this point and is still alive and kicking is doing well; it's almost impossible to call any such evolution "irrational", so finding ways to prove it so is just silly. I mean, there's plenty of evolution that seems odd... flightless birds, blind species with eyes, animals that eat their young and their mates... but these species all survive and procreate and carry on from one generation to the next. Why does everything have to be nice and tidy... what's the obsession with "rational"? In fact, the behavior described in the article sounds more rational than the opposite... consider Pandas, who exist almost entirely on one food (bamboo)... these animals are very nearly extinct due to this behavior (some people assert that they would be if it weren't for human efforts to save them). Is that rational from an evolutionary perspective?

I'm sure I sound annoyed, but some times we try to oversimplify things way too much. happy_place is correct; competition could matter, and individual preference clearly exists all over the place... why does there have to be a rationalization? Is it an evolutionary benefit that happy_place likes dark chocolate while their wife hates it? More likely it's just a quirk of evolution, not a grand result of evolution having evolved precisely so that our species won't starve when cocoa is the last remaining food on the planet.

Let me put it this way... given whole of evolution, I would wager that for any categorization of traits that are well defined (such as "rational"), there exists at least one example that is both in and out of that category. SOMETHING has evolved irrationally, oddly, stupidly, and without purpose, due only to quirks of evolution that didn't really get in the way of a species survival, but didn't necessarily help it along either.

Add to that, many of those "researchers" have little actual knowledge about the animals involved, only focusing on the traits that appeal to their line of investigation. This is most easily spotted when they cross genus - hell, cross Order - boundaries to make comparisons. Birds and insects do not share the same drives, for instance.

There is great value in looking at behavior that appears to be irrational and trying to figure out what unconsidered factor makes it rational after all.

For example, the pandas. It may be that their dietary choice is a problem for them now, but prior to the dominance of another species that can and will slash and burn a whole forest, if you're going to depend on a single food, one that grows so fast you can sometimes actually see it growing isn't a bad choice.

They are using the word "rational" to describe a specific, common-sense-to-humans, transitive property of preferences. That is all. You are reading way to much into their choice of words. The whole point of evolution by natural selection is that certain traits emerge because they are adaptive. What this paper sets out to show is that the behavior we see is not "rational" in the common sense, but it is still adaptive. It did not evolve "due to an absurd amount of chaos." They're basically arguing that long-t

It's reasonable to expect evolution to select for the Big Three: sexual preference, predator avoidance, and efficient food gathering. If evolution doesn't select for efficient food gatherers, what does it select for?

The logical fallacy I'm worried about is expecting an experiment to display only a bias for "efficient food gathering". It could be that the extra energy spent in wandering farther for food may be worth it in a natural setting to avoid predators, or avoid stale food, or the exercise may aid in digestion. Maybe the birds liked to hide in the tube, maybe some thought they'd feel trapped. Other people have made plenty of other observations on this post with alternate theories, but there are many many possib

Your comment and and the article remind me of strategies employed in voting systems. Arrow famously put forth arrows axioms of fairness for selecting a voting system, one of those axioms was the irrelevance to alternatives when comparing two canadidates. that is, your preference for candidate A over candidate B should not change if candidate C runs or not. We also believe that preferences are transitive, and transitivity should mean you can rank your preferences in a set of candidates. The interesting

Oops, I deleted a key point from my comment. Arrows result shows that even if every individual has a transitive preference order, that a group does not always have a transitive preference order. in terms of Condorect voting this would mean that under rare cases one can have A > B, B > C and C>A, which is a non-tranistive cycle for the groups combined preferences.

Thus one way to explain non-trainsitive behaviour in individuals would be to postulate that internally individuals are groups! you

Yes, I agree. Approval voting has much to be desired, especially it's simplicity of implementation and its assymtotic approach to rangevoting without all the complexity. I was discussing instant run-off voting and how transitivity violations arise so I did not bring this up.

Not just any given food source but... there is a base assumption in this simplified "logic" that any once choice is necessarily viable as an only option. What if no member of the set A, B, or C, provides all of the needed nutrients? Sure I can eat A preferencially, but, if I eat it to exclusion, that means that I live chronically with any deficits in what it provides.

Since its unlikely that any given organism can fully distinguish its own nutritional needs compared to a single food source, drawing from mult

Rock, Paper, Scissors (Lizard, Spock). If you prefer Rock and all three options are available, you'll favor Rock. However, if you know that Paper has been eliminated as a choice, you'll pick Scissors because Scissors beat Rock. Of course, in this sort of set-up, I would guess that there wouldn't be a group bias towards any one resource (individual bias, but not a group bias).

Yes, but this has nothing to do with a violation of transitivity... It is just that their model for food attractiveness which was wrong. If you correct the model, then you should get back transitivity (basic optimizations rule).

No, the corrected model would incorporate the reason for breaking transitivity. Transitivity would still be broken, we would just have an explanation for it.

Transitivity is broken in many ways. I once had a set of game spinners that proved this. Spinner A would on average beat Spinner B (stop on a higher value), Spinner B would on average beat Spinner C, but Spinner C would on average beat spinner A kind of a neat trick.

My point is more about the Mathematical objects rather than the thinking. Your last example does not matter as it is not an ordered set. Although, as I said in my first message, I think that they should not say that transitivity is broken but rather that the food attractiveness function can be changed by some events, thus reordering the elements in the set Foods. Or that Foods is not an ordered set and thus, no comparison operator can be applied.

" think that they should not say that transitivity is broken but rather that the food attractiveness function can be changed by some events, thus reordering the elements in the set Foods."

But they didn't say that, because that would have been incorrect.

Indeed, transitivity does not always hold for inequalities, and this is a known mathematical fact. The article doesn't try to change that (as you suggest), but rather acknowledges that this phenomenon, in the context of preferences, can also be rational.

Make no mistake: many situations involving inequality do not display the property of transitivity. This is not a problem with the math, nor does it mean anything is "broken". There is not

Maybe you need to refresh the definition of a comparison operator : Partially Ordered set. In short : you can not have an ordering comparison relation and not having transitivity for it. Period. So either it is an ordered set (like \mathbb{R}) and you can use a comparison operator or it is not (like \mathbb{C}) and you cannot use any ordering relation.

Maybe you need to refresh the definition of a comparison operator : Partially Ordered set. In short : you can not have an ordering comparison relation and not having transitivity for it.

Maybe you need to brush up on your inequalities. I assure you that in the real world some inequalities (such as preferences) are not transitive. I have already explained one situation in which that is true, and you can prove it for yourself.

Flip a coin 3 times. Write down the result: HHH, THT, etc. There are 8 combinations. The game is played this way: you write down your prediction. I write down mine. NO MATTER WHICH prediction you make (if of course you make it first), I can choose another combination

OK, let's see : I am not familiar with this game and I don't know if you your selection and random event are ordered (not in the sense of the discussion on the sets we have but on the order of the events to appear : if I say, for example, 'HTH' does the sequence of random events must exactly match 'HTH' or 'HHT' and 'THH' are also considered a match)?

For the following few lines I will consider that this is true (while I think that it is false from the table you gave, but I don't think that it is changing an

"For the following few lines I will consider that this is true (while I think that it is false from the table you gave, but I don't think that it is changing anything on the model of the game we are debating on, correct me if I am wrong):"

Pardon me. You are correct: I did not describe the game properly. Let me start from the beginning.

We agree that there are 8 possible combinations that can occur in 3 coin flips: HHH, HHT, etc.

The way the game is played is that player A chooses one of those combinations, and player B chooses one of those combinations (presumably a different one; there would be no point in choosing the same one). Then a coin is flipped until one of those combinations appears. The winner is the person whose chosen combin

But they say, "well, we think it's this way," and a lot of people take it for gospel. That is, until some other group of researchers does another flawed experiment that produces another incorrect, different result. Rinse, repeat.

If you want absolute certainty, you probably aren't interested in science.

I'm less interested in absolute certainty, and more interested in having research done correctly, not biased or influenced by personal philosophy. Opinion has no place in the laboratory, unless we're experimenting on opinions.

But they say, "well, we think it's this way," and a lot of people take it for gospel. That is, until some other group of researchers does another flawed experiment that produces another incorrect, different result. Rinse, repeat.

That's how we learn. Find the flaws in previous research and develop a new method without those flaws, fully understanding that you won't get it right either. The research is still useful, even if all it does is point out an area we don't fully understand.

Opinion has no place in the laboratory, unless we're experimenting on opinions.

I think you're both right, both saying the same thing, the OP just did so in a more cynical fashion. The important thing that the headline muddles is that there are no actual transitivity violations being observed, only seeming transitivity violations, so headline proposes something false ("why transivity [sic] violations can be rational').

Journalism wouldn't be interesting if the journalists understood the important minutiae of the scientific journals they refashion into pop articles.

And here we have someone whose biases are based entirely in the null hypothesis, using the null hypothesis to justify ignoring the conclusion. It's a good chance to see this behavior outside of its normal habitat of politics/religion.

Sometimes there a number of competing things which are important to consider, and there's no good single way to combine the various criteria into a single metric.

Yes, but I still claim we're saying the same thing. Each action (hummingbird or whatever) is based on factors present at the time the decision was made. They had assumed they understood the relationship between choices A, B, and C, but it turns out there's more to it than they initially thought.

My cynicism is based on them bringing transitivity into the paper at all. It looks to me more like a linear programming problem rather than transitivity.

Two of those are forms of transport and one is a fuel. They're not directly comparable. One might argue that "Gas > Car" simply because gasoline has so many more uses. Cars...are only really good for one major use case. You could power stuff from their batteries, but that's really a functionality of the battery rather than the car.